ive thrown in the towel

[72chevk20]

72 K20 w/ 350 stock everything. I am at the end of my knowledge. Here Is the readers digest version with all the facts. Running fine for months. Voltage regulator popped. Replaced and drove. Wanted to change coil just because, and points while I'm at it. Both replaced, adjusted points, ran beautiful. Test drive, fuel pump blew. Ran until float bowl went dry. Replaced fuel pump. Flooded while cranking, pulled all spark plugs and cranked for 5 seconds. Let sit overnight and installed new spark plugs. Cranked, no start. Pulled plug, checked spark, good. Turned motor by hand with finger over number 1 to find TDC, pulled cap, timing good. I can see fuel spraying when I cycle throttle. Disconnected fuel line and sprayed ether down the carb and I dont even get a cough, yet spark is there and timing is good. Compression on all 8 is right at 160. I'm out of ideas and I feel retarded that I got beat by a Chevy 350.
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[Longhorn 70]

My 70 did somthing similar. EVERYTHING worked and was in spec. Mr Tach had flaked out and when connected it would somehow make the spark week enough to not work.

Start simple. Go back to TDC and make sure the rotor tip points to the #1 wire tower
Make sure exhaust is getting out....don't fall for no banana in your tailpipe.
Crank it for a few...... look for wet plugs.

Look also for cam timimg....Pull a valve cover and make sure at TDC both valves are closed.

[vectorit]

Welcome to the forum!

Try not to get to frustrated on this.
Have you rechecked the points? The new ones could have malfunctioned, I have seen new points fall apart shortly after running them or even while adjusting them.

Make sure you are on compression stroke TDC, and then work backwards from there.

[DorianB]

I agree with going back to basics.. Recheck spark plug connections and also make sure they are going to the correct locations!

[cleszkie]

You have fuel and spark, so my guess is that your timing is off or your valves are not adjusted properly. Did you pull and reinstall the distributor between it running and not wanting to run? Did you do any valve adjustments? What initial timing are you using? SBC won't like 0 degrees at TDC.

[BrianV]

Remove the points dist and replace with an HEI dist best money you will ever spend then as everyone else said start from scratch and you should find the problem

[ole dollor]

first let me say welcome to the forum from Texas, then double check your coil and see if you might have crossed the pos. and neg. wires. i have seen this before...worth a look.

[AusTx68]

Originally Posted by brianv

remove the points dist and replace with an hei dist best money you will ever spend then as everyone else said start from scratch and you should find the problem

x2!

[70blackfish]

x3

hei is your friend

[piecesparts]

Check timing, timing chain may have jumped a tooth, change dizzy to HEI (best thing you will ever do), check new coil for spark capacity. If not changing dizy, check pooints, capacitor, and inside of dizzy cap for fouling.

[72chevk20]

Checked everything 3 plus times. Points still good, coil still good, wires not crossed, timing still good. Going to pull the valve covers off today. But remember it ran great until the fuel pump went
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[Longhorn 70]

Hmmm...Do you still have fuel pressure? Oil pressure whilst cranking is good? Rotor turns in the dist?

HA! I said go to basics and now I just can't reach that straw.....

The fuel pump excentric is on the camshaft. Could this be related to timing chain? I can't think of a way that could affect cam timing....in this wacky world we live in almost anything is possible. Verify that valve timing is good and it hasn't jumped a few teeth....

[cdowns]

has truck set outside for awhile with gascap off r u sure u have good gas and not a wetyered down mixture that will not ignite

[GASoline71]

Originally Posted by 72chevk20

Checked everything 3 plus times. Points still good, coil still good, wires not crossed, timing still good. Going to pull the valve covers off today. But remember it ran great until the fuel pump went
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You say timing is good. What is it set at? initial timing? full advance timing? You have points, did you check the dwell?

Not sure how you found TDC by sticking your finger in the hole and rotating by hand. Unless you had your finger way in the hole and felt the piston. Remove #1 plug, and stick finger over the sparkplug hole. Then have someone bump engine with the starter. That will rotate engine hard enough to blow air past your finger with a whoosh. Then pull distributor cap to see if rotor is pointed in the general area of the #1 terminal. This will at least get you close to TDC where you can then fine tune.

Gary

[VetteVet]

To go along with what Cdowns is saying, since this happened after the fuel pump change
are you sure you are not still flooding the plugs. maybe you could disconnect the fuel line from the pump and hold down the accelerator until all the gas was out of the carb and then try some starting fluid. If you're getting a good hot spark and the truck ran fine until the fuel pump change. it almost has to be a fuel issue. Even if you had jumped time and the timing chain was sloppy you should still get some firing in the cylinders. A 160 PSI compression reading would tend to discount that and valve timing being out would lower the compression.

If the balancer outer ring has slipped and you have reset the timing since the fuel pump change it might explain the no start, but it still seems that it would misfire.

Another caution as you know you may have diluted the oil with the flooding gasoline so you may need to do an oil change before you drive it much after you get it running.

[70STOVEBOLT]

Is the spark at the plug blue/white or orange? It needs to be blue/white, especially if there is a flooding issue. I agree with electronic ignition being the way to go, but with that said, if points are adjusted properly and the wear parts are all replaced, it should run just as good. I replaced my points with a Pertronix Ignitor and I believe it is better than HEI, at least for a stock engine. Let the flaming begin...

[C5Phil]

::

Originally Posted by piecesparts

Check timing, timing chain may have jumped a tooth, change dizzy to HEI (best thing you will ever do), check new coil for spark capacity. If not changing dizy, check pooints, capacitor, and inside of dizzy cap for fouling.

[mrein3]

Originally Posted by 72chevk20

72 K20 w/ 350 stock everything. I am at the end of my knowledge. Here Is the readers digest version with all the facts. Running fine for months. Voltage regulator popped. Replaced and drove. Wanted to change coil just because, and points while I'm at it. Both replaced, adjusted points, ran beautiful. Test drive, fuel pump blew. Ran until float bowl went dry. Replaced fuel pump. Flooded while cranking, pulled all spark plugs and cranked for 5 seconds. Let sit overnight and installed new spark plugs. Cranked, no start. Pulled plug, checked spark, good. Turned motor by hand with finger over number 1 to find TDC, pulled cap, timing good. I can see fuel spraying when I cycle throttle. Disconnected fuel line and sprayed ether down the carb and I dont even get a cough, yet spark is there and timing is good. Compression on all 8 is right at 160. I'm out of ideas and I feel retarded that I got beat by a Chevy 350.
Posted via Mobile Device

You mentioned "fuel pump blew - Ran until float bowl went dry".
Did you confirm no fuel before you put the new pump on? The one SBC I owned that had the timing chain skip a tooth was an all stock configured 350. I started it, got out to brush snow off the windows while it was running fine on cold idle. While brushing off the car it simply stopped. Lucky me the shop I worked at was two blocks away. I pushed it up there, put on a new timing chain, and ran it ran fine again.

Long story short, my money is on the timing chain. If it skipped a tooth, you'll get a spark, just at the wrong time. Since you can't get it running, you have no way of knowing if the timing is right.

Since you've confirmed everyting else, it has to be the timing chain. Since you're working on a K20, that is an easy-peasy in-truck swap.

[72chevk20]

Gary, that's what I did. Finger not in the hole but over and yes, rotor lines up dead on.
So I found today that my new coil was bad. Showed good resistance on primary and secondary but very weak spark. Put new coil in and got good hot spark. Got it to cough a few times with starting fluid so I connected the fuel line back up, but again, still no start.
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[67ChevyRedneck]

I may be off, but I seem to recall reading that there were different fuel pumps that used a slightly different length rod. If you had one with the longer rod then replaced it with one that needed the shorter one, that could explain the flooding? With the crap parts the box store parts places sell now a days, I wouldn't be surprised if the fuel pump is bad either...

[bigguy69]

I have seen some plugs gas foul. Maybe switch out to a new set and see what it does. Especially since you said the coil was bad. Cheap place to start good luck on getting it running
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[LynnJr]

Pull all 8 plugs out of the engine and crank it over several times to blow out all that unburned fuel.Next use a cigarette lighter the burners on your gas stove or a propane torch to burn all the fuel off those spark plugs.
Let them cool off or when you go to install them they may pop on you from all the vapors still in the motor.
When you go to restart it don't pump the throttle.
Lynn

[72chevk20]

Jesse, i replaced the pushrod at the same time as the pump and they both measured the same length and diameter. I will change the plugs again, they are cheap enough.

[OhioDan]

Ya say ya run it until the carb ran dry? Needle valve in carb might be stuck? Are ya getting gas thru the carb? Tap on top of carb with small hammer (Imean small) or a screwdriver handle while trying to start. See if that helps?

[Littletony]

What is the gap on the plugs?